Question

Approximately how old is a fossil that contains 3.13% of its original carbon-14? The half-life of carbon-14 is 5730 years.A) 2870 yearsB) 5730 yearsC) 11,500 yearsD) 22,900 yearsE) 28,700 years

Answer 1

E

Step-by-step explanation:

The half life of a radioactive decay is the time taken for exactly half its original mass to be decomposed. For 3.13% to remain, it has decomposed a number of times.

Let's write a timeline. We should know that the original mass is 100%

100% to 50% to 25% to 12.5% to 6.25% to 3.125%

This shows that the sample had decayed 5 times. As we know, one half like take 5730years from the question. Hence, 5 will take 5730 × 5 = 28,650 years